TB Flashcards
TB in children vs adults
Children:
- <5yo more likely to have life-threatening TB disease as immunity lower
- and more likely to have disseminated TB (esp. miliary/meningitis)
- more likely to have TB disease from primary infection, vs activation of latent TB in adults
- most are SMEAR NEGATIVE
- rarely infectious: pattern of disease, low bacillary load + lack of coughing force
- unlikely to be index case!
TB - type of organism
gram positive obligate aerobe with wax wall
acid fast bacilli
which part of the lungs does TB tend to sit in?
upper lobes - obligate aerobe!
outline testing options for TB
- TST preferred for asymptomatic esp <5yo (less reliable <6mo)
- CI if previous TB or previous large reaction
- false positive if bcg vax esp early infancy, or NTM exposure - QFN-GOLD adolescents
interpreting the TST
- > =5 mm in children who have household contacts
- > =10 mm in children with history of close contact or endemic area
- > =15 mm in all other children
where might BCG vax scars be?
deltoid, forearm, thigh, scapulae
what size/location of LN do you have to expect TB in?
> 1cm in neck, >1.5cm in axilla, >2cm in groin, and do not improve within 1 week of anti-staphylococcal antibiotics
clinical spectrum of TB disease - what can it affect?
- asymptomatic: 80-95% infected children, 40-50% infected infants
- meningitis
- eyes
- pulmonary TB A) primary B) progressive C) chronic
- pleural effusion
- pericarditis
- abdominal
- kidneys - sterile pyuria
- bones - ponchet’s (arthritis), pott’s (spine)
- skin
- miliary TB
what is miliary tb
refers to TB spread haematogenously to >2organs
active TB in household contact - what do you do?
If <6mo: TPT whole course > TST at 6mo
If <2yo: TPT wjole course
If <5yo, start TPT regardless
- if initial TST neg: do break of contact repeat TST after 3mo
- — if negative break of contact > consider BCG vax
- if initial TST positive: do whole TPT course
main side effect of TPT (aside from non-compliance)
isoniazid-related hepatotoxicity; but this is rare in children and if baseline LFTs are normal, you wouldn’t have to monitor
active TB - what do you do now?
- contact trace
- notification to gov
- micrbiological and drug susceptibility testing
- imaging as required; CXR is a must
- medications
what type of Rx regimens for TB?
non-severe pulmonary or peripheral lymph node TB:
2 months RIP > 4 months RI
if adolescent, HIV positive, or severe child (inc sputum positive TB): add ethambutol to reduce resistance
+/- steroids e.g. severe miiary disease, compressive lymphadenopathy
children vs adult TB meds
- Children require higher mg/kg of antituberculosis drugs to achieve effective serum concentrations
- Adverse effects rare in children
efficacy of BCG vaccine in children
BCG is 70 to 80 percent effective against all forms of TB when administered at birth to mycobacteria-naïve infants
what are MDR TB or XDR TB?
MDR TB resistant to R/I XDR TB resistant to R/I/fluoroquinolone and one of 1. Amikacin 2. Capreomycin 3. Kanamycin
NTM - which do we care about?
mycobacterium avium - causes MAC (+ pulmonary disease)
mucobacterium kansaii - mimics MTB
mycobacterium ulcerans - Buruli ulcer!
buruli ulcer - how does it present?
incubation weeks-months
firm painless nodule > weeks > painless necrotic ulcer > OM, lymphoedema
treatment for buruli ulcer
thing to tell pts about the treatment
rifampicin + quinolone or clarithromycin 8 weeks
Treatment with antibiotics can sometimes cause a paradoxical inflammatory reaction and enlarging ulceration
MAC lymphadenopathy
indolent purple unilateral nontender usually <5yo
mycobacterium type of granuloma
caseating!
two common causes of atypical pneumonia in kids
mycoplasma pneumoniae
chlamydia pneumoniaea
afebrile pneumonia of infancy = what bug!
very young, up to 4mo
chlamydia trachomatis
rhinorrhea and tachypnea followed by a staccato cough pattern
exam thoughts - what = chlamydia pneumoniae?
atypical pneumonia
often worse than patient’s clinical status: mild , diffuse involvement/ lobar infiltrates
how to treat the atypical pneumoniaes?
a. Doxycycline OR azithromycin OR clarithromycin
b. Therapy usually for 7-10 days (except azithromycin which is used for 3-5 days)
mycoplasma pneumoniae - key thing to know for exams??
-
key associations*
1) skin: SJS/TEN, EM
2) neuro: demyelination, ataxia, bell’s, encephalitis
3) haem: DAT +ve haemolysis, cold Ab mediated disease
1/3 hilar lymphadenopathy
appear worse than the clinical exam
mycoplasma pneumoniae - what age group?
school aged children and up
what do mycoplasma hominis and urease urealtyicum have in common?
they are the genital mycoplasmas!
how can leptospirosis present
1) anicteric 90%, mild no mortality
- initial 3-7d septicaemic: blood only, constitutional sx
- second up to 1mo immune phase: recurrence of fever + aseptic meningitis/uveitis
2) icteric / Weil’s - 15% mortality
- initial septicaemic phase same
- second immune phase much worse: liver (jaundice), renal failure, thrombocytopaenia, CV collapse, haemorrhage
